Scientists have devised a new method to determine the average temperature of the oceans across the world. Researchers claim that this novel method can precisely estimate the changes in the temperature of the world’s oceans over the past 24,000 years by determining the concentration of some specific noble gases in the “air bubbles” trapped inside ice cores in Antarctica.
According to scientists, it almost an impossible task to determine the variations in the average temperature of oceans due to the distribution of different water layers that have a considerable difference in temperatures. However, it is possible to determine the average temperature of oceans indirectly by measuring the amount of krypton, xenon, and argon in the air bubbles trapped inside ice samples. It is because when oceans warm, they release xenon and krypton into the atmosphere in specific quantities (although argon levels are not preserved accurately). By calculating the ratio of xenon and krypton in the air bubbles trapped inside oceans, the average global ocean temperature can be easily calculated.
The current study was carried out by an international team of scientists, including those from the University of Bern, the Scripps Institution of Oceanography (University of California San Diego), and the Swiss Federal Laboratory for Material Science and Technology (EMPA). In this study, researchers focused on the ice cores in Antarctica that are believed to maintain an archive of the Earth’s atmosphere through trapped “air bubbles.” According to Phys.org, ice core samples were collected during the West Antarctic Ice Sheet (WAIS) Divide Ice Core project over six field seasons. Researchers used a drill to remove ice in 3.7-meter-long cylindrical samples and collected several samples spanning 8,000- to 24,000-years-old. The last sample was taken in 2011 from a depth of 3,405 meters. The analysis of these samples suggested that the modern ocean’s average temperature is 3.5 degrees C, and at the peak of the last ice age, this value was 0.9 degrees C.
According to the researchers, their new method estimated an increase of 2.6 degrees C in the average temperature of the world’s oceans over the past 10,000 years. The team claims their method is not only useful in estimating large-scale changes (such as the transition from the last ice age to the present warm age) but also for tracking current changes in the ocean temperature.
“Our study clearly shows that the basic idea—the connection between the concentration of noble gases in the atmosphere and the average ocean temperature—is correct and that the method works,” said Bernhard Bereiter from the Scripps Institution of Oceanography.
The detailed findings of the study were published in the journal Nature.